CHEK1 and lung cancer: Indeed, nuclear fragmentation was observed to increase 24–72 h post irradiation following pre-treatment with the Chk1 inhibitor AZD7762 in p53-mutant H460 lung cancer cells [103], further supported by observations of a similar increase in nuclear fragmentation at 24 h following CEP-3891 pre-treatment in U2OS cell lines, shown to be as a result of abnormal chromosomal segregation [112].